Chlorhexidine represented by the formula ##STR1## is a compound, which was developed in 1954 as a disinfectant, exhibits disinfecting effect on a wide range of general bacteria and is used in a very wide area because of its quick effect and low toxicity. Especially it is used as gluconate salt, which has high solubility in water, for disinfection of hands and fingers, operation localities and operation instruments in the medical field because of wide range germicidal activity.
However, chlorhexidine has a defect that it is less effective against some Gram-negative bacteria, especially Pyocyaneus bacilli. Further, recently Pyocyaneus bacillus strains and Pseudomonas cepacia strains, which are resistant to this drug, have been reported and now this is a problem in medical institutions. Chlorhexidine sometimes causes shock symptoms when it is administered to mucous membranes in a conventionally employed concentration and, therefore, administration thereof to mucous membranes other than conjunctivae is now prohibited.
Under the circumstances, a substitute for chlorhexidine, which retains the wide antibacterial spectrum of chlorhexidine and is provided with improved germicidal effect and medical applicability. That is, there is a demand for a chlorhexidine type disinfectant for medical use, which can be used in a low concentration so as to be safely applicable to mucous membranes, has improved germicidal activity especially against Pyocyaneus bacilli and is suitable as topical disinfectants for surgical operations.
V. D. Warner et al reported on dental plaque inhibiting (antiplaque) activities of bis-susbstituted 1,6-bis-biguanidohexane derivatives in Journal of Medical Chemistry, 1973, Vol. 16, No. 6, pages 732-733. It had been known that variation in the end substituents of 1,6-bis-biguanidine radically changes antibacterial activity of the compound. Warner et al reported that the bis-phenyl-substituted derivative exhibited no antiplaque activity, the bis-cyclohexyl-substituted and the bis-1-adamanthyl-substituted derivatives exhibited antiplaque activity at the same level as chlorhexidin or better and the bis(m-trifluoromethylphenyl) derivative exhibited superior antiplaque activity at lower concentrations.
It is more than twenty years since this report appeared and we know no report on further study on general germicidal activities of 1,6-bis-biguanidohexane derivatives.
We have taken up some .alpha.,.omega.-bis-biguanidoalkane derivatives and checked their antibacterial activities and we noted that 1,n-bis(N.sup.5 -m- or p-trifluoromethylphenyl-N.sup.1 -biguanido)-C.sub.3 -C.sub.10 alkanes exhibited excellent antibacterial activities.